Planar lighting device

ABSTRACT

A planar lighting device includes a circuit substrate, a plurality of light sources disposed on the circuit substrate, a reflection layer disposed on the circuit substrate, the reflection layer including a first region having a plurality of openings where the respective light sources are located, and a second region connected to the first region, wherein the second region is bent in a direction from the first region, a hole pattern having a plurality of holes provided in the second region of the reflection layer, wherein at least two holes of the hole pattern are different in size, and an optical sheet disposed on the light sources.

CROSS-REFERENCE PARAGRAPH FOR RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.14/161,284, filed Jan. 22, 2014, which claims the benefit of prioritypursuant to 35 U.S.C. §119(a) to Korean Patent Application No.10-2013-0007294, filed on Jan. 23, 2013, which are hereby incorporatedby reference as if fully set forth herein.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a planar lighting device and moreparticularly, to a planar lighting device including a light emittingdevice.

2. Discussion of the Related Art

Liquid crystal displays (LCDs) which are one type of displays are usedin a variety of monitors for televisions, notebook computers anddesktops as well as cellular phones.

Such an LCD does not self-emit light, thus requiring a light-emittingdevice to light a liquid crystal panel so as to display imageinformation.

A light emitting device of LCDs is bonded to a rear surface of a liquidcrystal panel and is thus referred to as a backlight unit. Thisbacklight unit forms a uniform surface light source and supplies lightto a liquid crystal panel.

A light emitting diode (LED) has a structure in which an n-typesemiconductor layer, a light-emitting layer and a p-type semiconductorlayer are stacked in a substrate and an electrode is formed on thep-type semiconductor layer and the n-type semiconductor layer. Regardinga principle of light generation by the light emitting diode, light ofthe light-emitting layer generated upon recombination between holes andelectrons injected from respective semiconductor layers is discharged tothe outside.

Such a light emitting diode constitutes a light emitting diode packagewhich is used as a light source of a backlight unit (BLU).

Such a backlight unit provides a planar light source toward the liquidcrystal panel, which is thus considered to be an example of a planarlighting device. The planar lighting device is considered to be a lightsource which uniformly emits light through a flat surface and has arelatively small thickness.

The planar lighting device improves luminous efficacy of a displaydevice and accomplishes structural slimness thereof.

When the light emitting diode is used as a light source of a planarlighting device, the light emitting diode may be a side type in whichlight is diffused to a side direction or a direct type in which light isemitted in a front direction. A method for uniformly diffusing lightemitted from the light emitting diode is required.

SUMMARY OF THE INVENTION

Accordingly, the present invention is directed to a planar lightingdevice that substantially obviates one or more problems due tolimitations and disadvantages of the related art.

An object of the present invention is to provide a direct-type planarlighting device which improves an edge luminance uniformity of theplanar lighting device.

Additional advantages, objects, and features of the invention will beset forth in part in the description which follows and in part willbecome apparent to those having ordinary skill in the art uponexamination of the following or may be learned from practice of theinvention. The objectives and other advantages of the invention may berealized and attained by the structure particularly pointed out in thewritten description and claims hereof as well as the appended drawings.

To achieve these objects and other advantages and in accordance with thepurpose of the invention, as embodied and broadly described herein, aplanar lighting device includes a plurality of light sources arranged ona first surface of a circuit substrate, the light sources mountedthereon, a light regulator disposed in an edge of the first surface, thelight regulator regulating luminance difference caused by difference indistance between a plurality of light sources close to the edge, and anoptical sheet disposed on the light sources.

The light regulator may include one or more reflectors for reflectinglight emitted from the light sources to an inside or an upper part of anarea defined by the first surface.

The reflectors may be discontinuously disposed in portions of the edgefar from the light sources.

The reflectors may be discontinuously disposed in portions of the edgecorresponding to areas between adjacent light sources close to the edge.

Each reflector may include a reflection plate or a reflection structurecontacting the edge.

The reflection plate or the reflection structure may have a curvedcross-sectional shape including a semi-circular, oval or circular arcshape or a polygonal cross-sectional shape including a triangular ortrapezoidal shape.

The reflector may include a reflection layer disposed along the edge,and a plurality of through holes provided in the reflection layer.

The through holes may change in size according to positions relative tothe light sources.

The light regulator may include one or more absorbers for absorbinglight emitted from the light sources.

The absorbers may be discontinuously disposed in portions of the edgecorresponding to areas between light sources close to the edge.

The light regulator may include a plurality of reflectors for reflectinglight emitted from the light sources to an inside or an upper part of anarea defined by the first surface, and one or more absorbers disposedbetween the reflectors.

The reflection layer may be disposed on the first surface.

The light regulator may be formed by bending the reflection layer.

Meanwhile, the light regulator may be provided at least one side of fouredges of the first surface.

In accordance with another aspect of the present invention, a planarlighting device includes a plurality of light sources mounted on a firstsurface of a circuit substrate such that the light sources are spacedapart by a predetermined distance, a light regulator discontinuouslydisposed in at least one portion of an edge of the first surface, thelight regulator regulating luminance difference caused by difference indistance between a plurality of light sources close to the edge byreflecting or absorbing light, and an optical sheet disposed on thelight sources.

It is to be understood that both the foregoing general description andthe following detailed description of the present invention areexemplary and explanatory and are intended to provide furtherexplanation of the invention as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide furtherunderstanding of the disclosure and are incorporated in and constitute apart of this application, illustrate embodiments of the disclosure andtogether with the description serve to explain the principle of thedisclosure. In the drawings:

FIG. 1 is a sectional view illustrating an example of a planar lightingdevice;

FIGS. 2 and 3 are schematic views illustrating distribution of luminanceat an edge of a reflection surface according to position of lightsources;

FIG. 4 is a schematic perspective view illustrating a first example of aplanar lighting device including a light regulator;

FIG. 5 is a schematic view illustrating traveling of light seen from thecross-section taken along the line A-A of FIG. 4;

FIG. 6 is a schematic view illustrating traveling of light seen from thecross-section taken along the line B-B of FIG. 4;

FIG. 7 is a schematic view illustrating an example of luminanceregulation by the light regulator;

FIG. 8 is a schematic perspective view illustrating a second example ofa planar lighting device including a light regulator;

FIG. 9 is a schematic view illustrating traveling of light seen from thecross-section taken along the line C-C of FIG. 8;

FIG. 10 is a schematic view illustrating traveling of light seen fromthe cross-section taken along the line D-D of FIG. 8;

FIG. 11 is a schematic view illustrating an example of luminanceregulation by the light regulator;

FIG. 12 is a schematic perspective view illustrating a third example ofa planar lighting device including a light regulator;

FIG. 13 is a schematic view illustrating traveling of light seen fromthe cross-section taken along the line E-E of FIG. 12;

FIG. 14 is a schematic view illustrating traveling of light seen fromthe cross-section taken along the line F-F of FIG. 12;

FIG. 15 is a schematic view illustrating an example of luminanceregulation by the light regulator;

FIG. 16 is a schematic perspective view illustrating a fourth example ofa planar lighting device including a light regulator;

FIG. 17 is a schematic view illustrating traveling of light seen fromthe cross-section taken along the line G-G of FIG. 16;

FIG. 18 is a schematic view illustrating traveling of light seen fromthe cross-section taken along the line H-H of FIG. 16;

FIG. 19 is a schematic view illustrating an example of luminanceregulation by the light regulator;

FIGS. 20 to 23 are sectional views illustrating examples of a reflectionplate;

FIGS. 24 and 25 are sectional views illustrating examples of areflection structure; and

FIGS. 26 and 27 are schematic perspective views illustrating examples ofconfigurations of the light regulator.

DETAILED DESCRIPTION OF THE INVENTION

Reference will now be made in detail to the specific embodiments of thepresent invention, examples of which are illustrated in the accompanyingdrawings.

However, the present invention allows various modifications andvariations and specific embodiments thereof will be exemplified withreference to drawings and be described in detail. The present inventionshould not be construed as limited to the embodiments set forth hereinand includes modifications, variations, equivalents, and substitutionscompliant with the spirit or scope of the present invention defined bythe appended claims.

It will be understood that when an element such as a layer, area orsubstrate is referred to as being “on” another element, it can bedirectly on the element, or one or more intervening elements may also bepresent therebetween.

In addition, it will be understood that although terms such as “first”and “second” may be used herein to describe elements, components, areas,layers and/or regions, the elements, components, areas, layers and/orregions should not be limited by these terms.

FIG. 1 is a sectional view illustrating an example of a planar lightingdevice.

The planar lighting device 20 may be disposed on a lower cover 16 and aliquid crystal panel (not shown) may be disposed on the planar lightingdevice 20.

The planar lighting device 20 includes a plurality of light sources 22mounted respectively on a plurality of circuit substrates 21 disposed inan upper part of the lower cover 16. Each light source 22 may be mountedby surface-mounting a light emitting diode (LED) package on the circuitsubstrate 21.

The light source 22 including the light emitting diode (LED) packageincludes a pair of electrodes 222 passing through a sub-mount substrate221, an LED 223 connected to and mounted on the electrode 222, and aphosphor layer 224 containing a silicone resin mixture disposed outsidethe LED 223.

The phosphor layer 224 may have a planarized upper surface and thephosphor layer 224 may be provided on the upper surface with an opticallayer 225 having optical property such as reflectivity or transmittance.

The optical layer 225 may be formed of a material prepared by mixing aresin with phenyl propanol amine (PPA), epoxy molding compound (EMC),micro-cell polyethylene terephthalate (MCPET), silver (Ag) and aluminum(Al) having reflectivity, and a bead of Ti, Al, Ag, SiO₂ or the like,exhibiting reflectivity, transmittance or refraction.

Light emitted upward from the LED 223 through the optical layer 225 isreflected in a side direction of the phosphor layer 224. The LED 223 isa blue LED and the phosphor material constituting the phosphor layer 224is a yellow phosphor, thus rendering white light to be emitted from thelight source 22.

The circuit substrate 21 on which the light source 22 is mounted may bedisposed on a mount groove 161 disposed on the upper surface of thelower cover 16. In addition, a plurality of mount grooves 161 includingthe mount groove 161 may be spaced from one another by a predetermineddistance and circuit substrates 21 including the circuit substrate 21disposed respectively in the mount grooves 161 may be also spaced fromone another by a predetermined distance. Accordingly, the light sources22 may be spaced from one another by a predetermined distance on thelower cover 16.

The light sources 22 may be disposed in one line or a zigzag form.

A reflection layer 23 may be disposed in a gap between the light sources22 disposed on the circuit substrates 21. Accordingly, the light sources22 protrude from an upper surface of the reflection layer 23.

In addition, a transmission regulation layer 15 having a pattern ofholes 151 transmitting light, which is spaced from the reflection layer23 by a predetermined distance, may be disposed on the reflection layer23.

The transmission regulation layer 15 may utilize a reflective sheetwhich transmits some of light emitted from the light source 22 andreflects the remaining light again.

The transmission regulation layer 15 is a hole patterned reflectivesheet having a plurality of holes 151 on an upper surface thereof. Thatis, light discharged from the light source 22 through the holes 151 orreflected by the reflection layer 23 passes through the holes 151, andlight travelling in other regions is reflected to the reflection layer23 again or is refracted or reflected by a spacer 25.

In addition, radiuses of the holes 151 increase with increasing distancefrom a center of the light source 22, thus passing more light than isreflected with increasing distance from the light source 22.

That is, the holes 151 are disposed such that the size of the holes 151is the smallest in the closest position to the light source 22 and isthe largest in the middle between two adjacent light sources 22.

In addition, the holes 151 are disposed such that sizes of the holes 151gradually increase from the closest position to the light source 22 tothe middle position between two adjacent light sources 22 and decreasefrom the middle position between the two adjacent light sources 22 tothe closest position to the light source 22.

The reason for this is that intensity of light increases as the lightsource becomes closer to the light source 22 and decreases as the lightsource becomes farther from the light source 22. Preferably, lighttransmission increases as a distance from the light source 22 increasesand decreases as the distance from the light source 22 decreases so thatluminance of light is uniformly maintained throughout the entire surfaceof a display using such a planar lighting device.

Light emitted from the light source 22 is diffused in a side directionthrough the gap between the reflection layer 23 and the transmissionregulation layer 15. The diffused light is emitted in an upper directionthrough the pattern of the holes 151. As such, the area between thereflection layer 23 and the transmission regulation layer 15 is definedby a light-guide layer 24.

The light-guide layer 24 may be formed by a spacer 25 enabling apredetermined gap between the reflection layer 23 and the transmissionregulation layer 15 to be maintained.

That is, the spacer 25 functions to maintain the distance between thetransmission regulation layer 15 and the light source 22 and extends toa height corresponding to a designed height of the light-guide layer 24and a length corresponding to a length of the reflection layer 23.

The spacer 25 is formed of a material such as polycarbonate (PC),polymethyl methacrylate (PMMA), glass, a resin, phenyl propanol amine(PPA) or aluminum (Al) and thus exhibits light transmission, refractionor reflection.

In addition, the spacer 25 may be mounted by applying an adhesive to theupper and lower surfaces of the spacer 25 and performing UV curing orthermal curing.

In addition, optical sheets such as a diffusion layer 11, a lowerpolarizing plate 12, a color filter substrate 13 and an upper polarizingplate 14 may be disposed on the transmission regulation layer 15.

Meanwhile, the circuit substrate 21 may be fixed to the mount groove 161of the lower cover 16 by applying an adhesive 17 to a lower surface ofthe circuit substrate 21 and a lower surface of the reflection layer 23.In addition, the reflection layer 23 may be fixed to the circuitsubstrate 21.

FIGS. 2 and 3 are schematic views illustrating distribution of luminanceat an edge of a reflection surface according to position of lightsources.

As described above, in a direct-type planar lighting device, acombination of light emitted from the light sources 22 is emitted in thecenter of the surface on which the light sources 22 are distributed.Accordingly, luminance of the planar lighting device can be uniformizedusing the optical sheets 11, 12, 13 and 14 described above.

The surface on which the light sources 22 are distributed may be asurface of the circuit substrate 21 or an upper surface of thereflection layer 23 disposed on the circuit substrate 21. Hereinafter,the following description is provided under the assumption that thesurface on which the light sources 22 are distributed is the uppersurface (reflection surface) of the reflection layer 23.

Meanwhile, difference in luminance between areas close to the lightsource 22 and areas far from the light source 22 may be generated at anedge 26 in which distribution of the light source 22 is completed.

For example, as can be seen from FIGS. 2 and 3, as the disposition ofthe light source 22 is changed, luminance difference may be generatedaccording to the distance from the light source 22 at the edge 26 of thelight source 22.

That is, in a direct-type lighting device, luminance is high at theposition close to the light source 22 and luminance is low at theposition far from the light source 22 at an edge 26 of the upper surfaceof the reflection layer 23.

Accordingly, as shown in FIG. 4, preferably, a light regulator 300 forregulating luminance difference caused by distance difference betweenthe light source 22 and the edge 26 may be provided.

The light regulator 300 regulates luminance difference which may occurbetween the reflection layer 23 and the edge 26. That is, uniformity ofluminance can be improved at the edge 26.

Accordingly, when such a light regulator 300 is provided, light emittedfrom the light sources 22 may be more uniform. More preferably, moreuniform lighting can be implemented with the transmission regulationlayer 15 having the pattern of holes 151 and the optical sheets 11, 12,13 and 14 disposed on the reflection layer 23 and the light source 22.

As an example, the light regulator 300 may include a plurality ofreflectors 30 for reflecting light emitted from the light sources 22 toan inside of an area formed by the reflection layer 23, disposed at theedge 26 of the reflection layer 23.

For example, the reflectors 30 are disposed in portions of the edge 26farther from the light sources 22 so that the reflectors 30 reflectlight travelling toward the edge 26 and thus focus surrounding lightupon relatively dark regions, thereby regulating luminance uniformity.

As shown in FIG. 4, the reflectors 30 may be discontinuously disposed atthe edge 26 in the positions relatively far from the light sources 22.That is, the reflectors 30 with a predetermined width may bediscontinuously disposed along the edge 26 in the positions farther fromthe light sources 22.

In addition, from another point of view, the reflectors 30 may bediscontinuously disposed in portions of the edge corresponding to areasbetween adjacent light sources 22 close to the edge 26. That is, thereflectors 30 with a predetermined width may be disposed in portions ofthe edge corresponding to areas between two light sources 22 close tothe edge 26.

FIG. 5 shows traveling of light seen from the cross-section taken alongthe line A-A of FIG. 4, and FIG. 6 shows traveling of light seen fromthe cross-section taken along the line B-B of FIG. 4. In addition, FIG.7 is a schematic view illustrating an example of luminance regulation bythe reflector 30.

As shown in FIG. 5, the reflector 30 is disposed in a portion of theedge 26 in the position farther from the light source 22 so that lightemitted from the light source 22 is reflected through the reflector 30and brightness of area which may be dark due to great distance from thelight source 22 are thus reinforced.

In a portion of the edge 26 in the position closer to the light source22, light travels without being reflected in the portion of the edge 26to prevent the area from becoming brighter and thereby regulateluminance, as shown in FIG. 6.

In addition, as shown in FIG. 7, light emitted from the light source 22close to the edge 26 is also reflected by the reflector 30 and travelstoward areas farther from the light source 22. Accordingly, such areflector 30 uniformizes luminance of the light sources 22 close to theedge 26 and of the light sources 22 far from the edge 26.

As shown in FIG. 8, as another example, the light regulator 300 includesa plurality of absorbers 31 for absorbing light emitted from the lightsource 22. The absorbers 31 may be disposed at the edge 26 in positionscorresponding to the light sources 22 close to the edge 26.

Such an absorber 31 is close to the light source 22 and absorbs light ofareas brighter than neighboring areas to darken the brighter areas andthereby regulate luminance uniformity.

As shown in FIG. 8, the absorbers 31 may be discontinuously disposedclose to the light sources 22 at the edge 26. That is, the absorbers 31with a predetermined width may be discontinuously disposed along theedge 26 in positions relatively close to the light sources 22.

FIG. 9 shows traveling of light seen from the cross-section taken alongthe line C-C of FIG. 8, and FIG. 10 shows traveling of light seen fromthe cross-section taken along the line D-D of FIG. 8. In addition, FIG.11 is a schematic view illustrating an example of luminance regulationby the absorber 31.

As shown in FIG. 9, in a portion of the edge 26 in the position fartherfrom the light source 22, light travels without being reflected in theportion of the edge 26, thereby regulating luminance.

As shown in FIG. 10, the absorber 31 is disposed along the edge in theposition of the edge 26 close to the light source 22 so that lightemitted from the light source 22 is absorbed in the absorber 31 withoutbeing reflected or passing through the absorber and brightness of areaswhich may be relatively bright due to small distance from the lightsource 22 are thus reduced.

In addition, as shown in FIG. 11, as described above, light emitted fromthe light source 22 close to the edge 26 is absorbed in the absorber 31and light emitted from the light source 22 far from the edge 26 passesthrough the absorber 31 without being absorbing therein. Accordingly,the absorber 31 contributes to luminance uniformity of the light sources22 close to the edge 26 and of the light sources 22 far from the edge26.

As shown in FIG. 12, the light regulator 300 includes a plurality ofreflectors 30 and a plurality of absorbers 31 which are alternatelydisposed, as another example of the light regulator 300.

That is, the light regulator 300 may include the reflectors 30 forreflecting light emitted from the light sources 22 to an inside of thereflection layer 23 and absorbers 31 being disposed between thereflectors 30 and absorbing light emitted from the light sources 22.

As such, the reflectors 30 and the absorbers 31 alternate with eachother and the light regulator 300 may be continuously disposed along anedge 26 of at least one side of the reflection layer 23.

Although FIG. 12 illustrates an example in which the reflectors 30 andthe absorbers 31 are provided in edges of upper and lower sides of areflection layer 23 for convenience, the reflectors 30 and the absorbers31 may be provided in edges of left and right sides thereof.

As shown in the drawing, the reflectors 30 having a predetermined widthmay be disposed along the edge 26 in positions of portions of the edge26 far from the light sources 22 and the absorbers 31 having apredetermined width may be disposed along the edge 26 in positions ofportions of the edge 26 close to the light source 22.

Each reflector 30 and each absorber 31 may have the same width. However,in some cases, the width of the reflector 30 may be greater than that ofthe absorber 31 and vice versa.

Each reflector 30 and each absorber 31 may have the same width. However,in some cases, the width of the reflector 30 may be greater than that ofthe absorber 31 and vice versa.

FIG. 13 shows traveling of light seen from the cross-section taken alongthe line E-E of FIG. 12, and FIG. 14 shows traveling of light seen fromthe cross-section taken along the line F-F of FIG. 12. In addition, FIG.15 is a schematic view illustrating an example of luminance regulationby the reflector 30 and the absorber 31.

As shown in FIG. 13, the reflector 30 is disposed along the edge in theposition of a portion of the edge 26 far from the light source 22 sothat light emitted from the light source 22 is reflected by thereflector 30 and brightness of areas which may be relatively dark due togreat distance from the light source 22 is thus reinforced.

The absorber 31 is disposed in a portion of the edge 26 close to thelight source 22, as shown in FIG. 14, so that light emitted from theclose light source 22 is absorbed in the absorber 31 and luminance ofareas which may be relatively bright is thus regulated.

In addition, as shown in FIG. 15, light emitted from the light source 22close to the edge 26 may be absorbed in the absorber 31 and lightemitted from the light source 22 far from the edge 26 is reflected bythe reflector 30. Light emitted from the light source 22 close to theedge 26 is reflected by the reflector 30 and luminance of areas whichmay be relatively dark is thus regulated.

That is, the reflector 30 and the absorber 31 regulate light emittedfrom the light sources 22 close to the edge 26 and light emitted fromthe light sources 22 far from the edge 26, thus contributing toluminance uniformity.

As shown in FIG. 16, as another example of the light regulator 300, thelight regulator 300 includes a reflection layer 32 disposed along theedge 26 and a plurality of through holes 33 provided in the reflectionlayer 32.

Although FIG. 16 illustrates an example in which the reflection layer 32and the through holes 33 are provided in edges of upper and lower sidesof the reflection layer 23 for convenience, the reflection layer 32 andthe through holes 33 may be provided in edges of left and right sidesthereof.

As shown in FIG. 16, the through holes 33 may change in size accordingto position relative to the light source 22.

That is, larger through holes 33 are disposed in areas closer to thelight source 22 and small through holes are disposed in areas far fromthe light source 22.

In addition, the size of the through holes 33 may be gradually changed.That is, the largest through hole 33 is disposed in an area relativelyclose to the light source 22, through holes 33 gradually decrease insize, with increasing the distance from the largest through hole and thesmallest through hole 33 is disposed in the position farthest from thelight source 22.

FIG. 17 shows traveling of light seen from the cross-section taken alongthe line G-G of FIG. 16, and FIG. 18 shows traveling of light seen fromthe cross-section taken along the line H-H of FIG. 16. In addition, FIG.19 is a schematic view illustrating an example of luminance regulationby the reflection layer 32.

As shown in FIG. 17, the reflection layer 32 having small through holes33 is disposed in a portion of the edge 26 relatively far from the lightsource 22 so that a small amount of light emitted from the light source22 passes through the through holes 33, most thereof is reflected, andbrightness of an area which may be relatively dark due to great distancefrom the light source 22 is thus reinforced.

In addition, a reflection layer 32 having large through holes 33 isdisposed in a portion of the edge 26 close to the light source 22, asshown in FIG. 18, so that a great amount of light emitted from the lightsource 22 passes through the through holes 33 and brightness of an areawhich may be relatively bright is thus regulated.

FIG. 19 is a schematic view illustrating travelling of light by thereflection layer 32 having through holes 33 with various sizes. That is,some of light emitted from the light source 22 close to the edge 26passes through large through holes 33 and the remaining thereof isreflected by a portion of the reflection layer 32 in which small throughholes 33 are disposed, thereby regulating luminance of areas which maybe relatively dark.

In addition, as most of light emitted from light source 22 far from theedge 26 is reflected by the reflection layer 32, luminance of areas,which may be relatively dark, is regulated and luminance uniformity canbe thus improved.

Meanwhile, the reflector 30 or the reflection layer 32 described aboveis shown as a form such as thin wall, but may be provided with areflection plate 34 whose cross-section has an inclined surface having apolygonal shape, as shown in FIG. 20.

That is, as shown in FIG. 20, a reflection plate 34 whose cross-sectionhas an inclined surface having a right-angled triangle shape is formedso that light emitted from the light source 22 travels upward.

In addition, regarding the shape for reflection, a reflection plate 35whose cross-section has a curved surface having a semi-spherical orcircular arc shape may be formed, as shown in FIG. 21. In some cases,the reflection plate 35 may have an oval curved surface.

That is, a reflection plate 36 whose cross-section has an inclinedsurface having a triangle shape is formed, as shown in FIG. 22, and areflection plate 37 whose cross-section has an inclined surface having atrapezoidal shape is formed, as shown in FIG. 23.

The reflection plate 37 reflects at least part of light emitted from thelight source 22 toward the upper surface of the reflection layer 23 andreflects the remaining light into an inside of an area formed by thereflection layer 23.

The reflection plates 34, 35, 36 and 37 having various shapes may beapplied to the shape of the reflector 30 or the reflection layer 32described above.

Meanwhile, the absorption layer 31 described above may be also formed asone of shapes that are the same as the reflection plates 34, 35, 36 and37.

As shown in FIG. 24, in a portion of the edge 26 in the position farfrom the light source 22, a reflection structure 38 for reducing thedistance between the edge and the light source 22 may be provided.

That is, in the portion of the edge 26 far from the light source 22, thedistance between the edge and the light source 22 is reduced using thereflection structure 38 and surrounding light is transferred to darkareas and luminance uniformity can thus be regulated.

The reflection structure 38 may be formed of a highly reflectivematerial. FIG. 24 shows the reflection structure 38 having an ovalportion, but the shape of the reflection structure 38 may be selectedfrom a variety of shapes such as curved shapes including circular orcircular arc shapes, and triangular or trapezoidal shapes.

Regarding the light regulator 300 including the reflector 30, theabsorber 31 and the reflection plate 32 described above, another lightregulator 300 newly produced is bonded to the edge 26 of the lightregulator 300, as shown in FIG. 26.

For example, as shown in FIG. 26, reflectors 30 and absorbers 31 whichalternate with each other are produced as separate structures and arethen bonded to the edge 26.

In addition, as shown in FIG. 27, a surface of the reflection layer 23may be bent in an inside direction to constitute the reflector 30.

That is, the reflection layer 23 is produced such that it has a portionserving as the reflector 30 and the portion is bent to constitute thereflector 30.

It will be apparent to those skilled in the art that variousmodifications and variations can be made in the present inventionwithout departing from the spirit or scope of the invention. Thus, it isintended that the present invention cover the modifications andvariations of this invention provided they come within the scope of theappended claims and their equivalents.

What is claimed is:
 1. A planar lighting device comprising: a circuitsubstrate; a plurality of light sources disposed on the circuitsubstrate; a reflection layer disposed on the circuit substrate, thereflection layer comprising a first region having a plurality ofopenings where the respective light sources are located, and a secondregion connected to the first region, wherein the second region is bentin a direction from the first region; a hole pattern having a pluralityof holes provided in the second region of the reflection layer, whereinat least two holes of the hole pattern are different in size; and anoptical sheet disposed on the light sources.
 2. The planar lightingdevice of claim 1, further comprising a spacer disposed between thereflection layer and the optical sheet.
 3. The planar lighting device ofclaim 2, wherein the spacer is formed of at least one material selectedfrom polycarbonate (PC), polymethyl methacrylate (PMMA), glass, a resin,phenyl propanol amine (PPA) or aluminum (Al), and thus exhibits lighttransmission, refraction or reflection.
 4. The planar lighting device ofclaim 1, further comprising a lower cover having grooves, wherein thecircuit substrate is located in one of the grooves.
 5. The planarlighting device of claim 4, wherein at least two circuit substrates aredisposed on the lower cover,
 6. The planar lighting device of claim 5,wherein the at least two circuit substrates are disposed on the lowercover and spaced apart by a predetermined distance.
 7. The planarlighting device of claim 1, wherein the light sources are mounted on thecircuit substrate such that the light sources are spaced apart by apredetermined distance.
 8. The planar lighting device of claim 1,wherein the light sources further comprise an optical layer.
 9. Theplanar lighting device of claim 1, wherein the second region is bent ata periphery of the first region.
 10. The planar lighting device of claim1, wherein the reflection layer is fixed to the circuit substrate by anadhesive.
 11. The planar lighting device of claim 1, wherein a size ofthe openings of the first region is greater than a size of the lightsources.
 12. The planar lighting device of claim 1, wherein the openingsare disposed in the first region and spaced apart by a predetermineddistance.
 13. The planar lighting device of claim 1, wherein the holepattern is located at a position where corresponding light sources arelocated.
 14. The planar lighting device of claim 1, wherein a pluralityof hole patterns is provided in the second region, and wherein the holepatterns repeat along the second region.
 15. The planar lighting deviceof claim 14, wherein the hole patterns repeat with respect tocorresponding light sources.
 16. The planar lighting device of claim 14,wherein the hole patterns are spaced apart by a predetermined distance.17. The planar lighting device of claim 1, wherein the holes of the holepattern increase and decrease in size repeatedly.
 18. The planarlighting device of claim 1, wherein neighboring holes of the holepattern are different in size.
 19. The planar lighting device of claim1, wherein the optical sheet comprises at least one of a diffusionlayer, a lower polarizing plate, a color filter substrate and an upperpolarizing plate.
 20. The planar lighting device of claim 1, wherein thesecond region is connected at four side edges of the first region. 21.The planar lighting device of claim 20, wherein the hole pattern isprovided in the second region connected at two side edges of the firstregion.
 22. A display device comprising: a lighting device including: alower cover; a circuit substrate disposed on the lower cover; aplurality of light sources disposed on the circuit substrate; areflection layer disposed on the circuit substrate, the reflection layercomprising a first region having a plurality of openings where therespective light sources are located, and a second region connected tothe first region, wherein the second region is bent in a direction fromthe first region; a hole pattern having a plurality of holes provided inthe second region of the reflection layer, wherein at least two holes ofthe hole pattern are different in size; an optical sheet disposed on thelight sources; and a spacer disposed between the lower cover and theoptical sheet; and a liquid crystal panel on the lighting device. 23.The display device of claim 22, wherein the hole pattern is located at aposition where corresponding light sources are located.
 24. The displaydevice of claim 22, wherein a plurality of hole patterns is provided inthe second region, and wherein the hole patterns repeat along the secondregion.
 25. The display device of claim 24, wherein the hole patternsrepeat with respect to corresponding light sources.
 26. The displaydevice of claim 24, wherein the hole patterns are spaced apart by apredetermined distance.
 27. The display device of claim 22, wherein theholes of the hole pattern increase and decrease in size repeatedly. 28.The display device of claim 22, wherein neighboring holes of the holepattern are different in size.
 29. A direct-type lighting devicecomprising: a lower cover; a plurality of circuit substrates disposed onthe lower cover and spaced apart by a predetermined distance; aplurality of light sources mounted on each of the circuit substratessuch that the light sources are spaced apart by a predetermineddistance; a reflection layer disposed on the circuit substrates, thereflection layer comprising a first region having a plurality ofopenings where the respective light sources are located, and a secondregion connected to the first region, wherein the second region is bentin a direction from the first region; a hole pattern having a pluralityof holes provided in the second region of the reflection layer, whereinat least two holes of the hole pattern are different in size; an opticalsheet disposed on the light sources; and a spacer disposed between thelower cover and the optical sheet.